(1) As a Navio2 and ArduPilot user, why would I choose either the Stretch or Jessie image? Is there and advantages to either with regards to Navio2?
(2) If I am running a Navio2 on the older version (I think around May 2017, the one that first used sysctl), can I upgrade to this new version using the:
I read somewhere that it should be possible to update from Jessie, but a clean install i recommended
Upgrading an existing Jessie image is possible, but is not guaranteed to work in every circumstance. If you wish to try upgrading a Jessie image to Stretch, we strongly recommend taking a backup first – we can accept no responsibility for loss of data from a failed update